Why the modem does not see the SIM card and what to do in this case

Many use modems of mobile operators, because it allows you to access the Internet from a laptop anywhere, and in the villages often there is simply no alternative. But sometimes a problem happens - the modem simply does not see the SIM card. Because of this, of course, it’s impossible to go online. Such a situation is far from uncommon, and can happen with a variety of modems and with any carrier. Any user of such devices at least once faced with a similar situation and solved it in different ways. On the prevalence of the problem says a lot of discussions on this topic in different forums. We summarize the information and consider all possible situations when the 4G modem does not see the SIM card and what can be done about it.

Troubleshooting a modem.

Possible reasons why the modem does not see SIM

Such a problem can manifest itself in different ways:

  1. The specific inserted SIM is not detected.
  2. One card does not work, but on the other, the same operator, everything is fine.
  3. In general, no SIM card works, a message appears about its absence.

You need to understand that a SIM card is a rather complicated device, and not just a piece of plastic. In fact, it is a microcomputer with its own processor, programmed to work with a specific mobile operator. This device may have a manufacturing defect. On the other hand, the modem is also not easy, and there may also be various faults in it. Moreover, all parts are mounted on the board and are sensitive to external influences. That is, it can be broken by simply dropping it to the floor. For example, soldering a slot on impact will break away from the board and the problem is ready. Therefore, the source of such trouble can be both a modem and a SIM-card, although more often it is still the first one, because of its design, different build quality and fragility. Now consider all of the options listed in order and try to identify the fault.

What can be done

The options for action depend on the occurrence of the fault. So, if the 4G-modem does not see a certain SIM-card, you should try to insert it into the phone and check the operation, for example, just check its balance. If it is ok, the reason is in the modem. And if it does not work in the phone, you will have to contact the communications salon for a replacement. You also need to make sure that the SIM of the desired operator is inserted. The fact is that USB-modems are usually tied to it, and do not work with another, unless they change the firmware to universal. Therefore, for example, a SIM card from MegaFon will not work in a modem from MTS.

If the modem does not detect any SIM card at all, then most likely it is just defective or in need of repair. You can return it to the salon for an exchange, if it is new, or take it to a service center for repair. To be sure, you can try to insert into it another SIM card of the same operator, for example, from the phone. If the same thing is repeated, then the modem is definitely faulty. Sometimes the problem is software, and then it helps to remove the program and re-install it. If possible, it is useful to test performance on another computer.

There is also a situation when, after installing and removing the program of one operator, another one from another operator does not work - it does not start or displays error messages. For example, if a Beeline modem was used, then its software was removed and installed from the MTS, then the latter may not work. This happens with old devices for which the program is installed as a separate application. Finally, there is a very simple case, when a SIM card is simply inserted incorrectly, by the wrong side. This usually happens in a hurry or inattention, because next to the slot there is always a designation of how to insert correctly.